Sphygmometer apparatus



April 23, `1963 E- NEWLAND ETAI- 3,086,513

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1N VEN TORS A. E. NEWLAND :E1-AL 3,086,513

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a 1 Ilm @Ella United States Patent O 3,086,513 SPHYGMOMETER APPARATUSArthur E. Newland, Bedford, and Arthur J. Schultz, Indianapols, Ind.,assignors, by direct and mesne assignments, of forty percent to saidNewland, five percent to Mildred Pratt, Decatur, Ill.; two percent toIrvin E. Huckleberry, Salem, Ind.; twenty percent to Steven Sohacki,Gary, Ind.; ive percent to Richard H. Woolery, Bedford, Ind.; threepercent to Alex M. Clark, In-

dianapolis, Ind.; live percent to `lohn K. Spears, Paoli, Ind.; and tenpercent each to L. E. Cornwell of Indianapolis, Ind., and The IndianaNational Bank of Indianapolis, executors of Paul Henry Cornwell,deceased Filed June 1, 1959, Ser. No. 817,183 6 Claims. (Cl. 12S- 2.05)

This invention relates generally to ia blood pressure indicator and,more particularly, to a blood pressure indicator which may be operatedautomatically, either in response Vto a manually actuated electricalswitch or a coin operated electrical switch.

Our United States Letters Patent No. 2,865,365 granted December 23,1958, discloses an electrically operated sphygmometer. The patentedsphygmometer is intended to cooperate with a pneumatic system forinating 'a pressure cult operatively associated with a persons body in amanner to constrict .a blood vessel. An electrical system cooperateswith a pressure cuff in a manner to provide indications of systolic |anddia-stolic pressure. 'Ihe apparatus illustrated in the patent does notinclude rauxili` ary apparatus for enabling use of the sphygmometer asian automatically operable device. No controls rare included in thesystem whereby a person can conveniently and quickly apply ya pressurecuff to his body, operate an electrical switch and obtain an indicationof his blood pressure.

Accordingly, the primary object of this invention is to provide aisphygmometer or blood pricssure indicator adapted for operation inpublic places in ja manner similar to conventional vending machines bywhat might be termed a customen having no medical skill, whereby thecustomer may operate the indicator to produce an indication of his ownblood pressure.

Another object of this invention is to provide a coin oper-ated bloodpressure indicator device.

Still another object of this invention'is to provide a coinoperatedblood pressure indicator device adapted automatically to measurea persons blood pressure and provide sustained indication of systolicpressure for a predetermined interval of time. p

In accordance with lthis invention there is provided a blood pressureindicating device comprising a pneumatic system including therein apressure cuff forapplication to a persons body, a manometer forindicating pressure in said cuit, and 'a systolic valve for isolatingsaid manometer from the remainder of the pneumatic system, and anelectrical system -for controlling the operation of said pneumaticsystem comprising means for detecting pressure pulses in said cuff,means for amplifying -said pulses, and

means tor [detecting the occurrence of a systolic pulse and.

operatively associated with said systolic Valve for closing said valvewhen systolic pressure occurs in said cuff.

The full nature of the invention will be understood from theaccompanying drawings and the following description and claims.

FIG. l is a schematic diagram of the pneumatic pressure system asprovided in accordance with this invention.

FIG. 2 is a circuit diagram illustrating the electrical circuit forcontrolling the pneumatic system of FIG. 1.

This invention comprises -a pneumatic system having a motor driven aircompressor 10 connected by a tube 11 with an emergency dump valve 12which, in turn, is con- 3,086,513 Patented Apr. 23, 1963 ice nected bymeans of a tube 14 to an inflatable cuff 15. An indicating manometer 16is connected through a tube 17, a systolic valve 18 and a tube 19 withthe cuil 15. For insuring that the pneumatic system will not exceed Iapredetermined high pressure, there is provided a high pressure limitswitch 20 connected to tube 11 by means of a tube 21, and for providinga minimum pressure in the pneumatic system, a low pressure limit switch22 is coupled to tube 11 by means of a tube '23. There is also provideda bleeding rate control device 24 connected with tube 11 by means of latube 25.

It is intended in accordance with this invention to pro`V vide a controlsystem wherein the inatable cuff 15- may be inflated automatically aftera person inserts his a-rm within the cuff and in response to a coinoperated device. The system will automatically control the systolicvalve 18 in such a manner that the manometer 16 wil-l provide anindication of systolic pressure within a persons body after Whi-ch theentire system will be re-stored to its idle condition in preparation foranother cycle of operation.

Referring to FIG. 2 of the drawings there is provided a transducer whichmay be mounted in any suitable manner in cooperation with the culi 15 sothat the transducer will be in intimate contact with the persons arm insuch a position that the transducer may respond to blood llow within avein. Transducer 30 is coupled to ground,

as indicated, and also to a filter unit 31 which has a low passcharacteristic for removing all 4sonic or audible pulses which may begenerated by the transducer. Only very low frequency pulses appear inthe output of the filter, and these pulses repre-sent only the motion ofa blood vessel as systolic pressure occurs therein.

. The output of filter 31 is coupled to a first amplifier stage 32 whichmay be any conventional electron tube amplifier. The output of amplifierstage 32 is coupled in conventional manner to a second conventionalamplitier stage 33t. The output of this amplifier stage is coupled inconventional manner to a computer stage or electronic switch stage 34which comprises a gas filled thyratron tube 35. There is provided in thecathode circuit of this 4tube an adjustable resistor 36, the purpose ofwhich is -to adjust the firing level of tube 35. Adjustment of theslider 37 to the right increases the voltage on the cathode of tube 3Sin a positive direction whereby the control grid becomes relatively morenegative. Conversely, adjustment of the slider to the left decreases thevoltage on lthe cathode, making the grid relatively more positive. Thus,the level of the signal applied from ampliiier stage 33 to the controlgri-d of tube 35 may be adjusted upwardly or downwardly for determiningthe level of input signal which may be sufficiently positive to firetube 3S and cause it to become conductive. Normally open low-pressureswitch 22 connects the cathode of tube 3 5Vto ground -to preventoperation of tube 35 as will be described. A relay 38 is connected tothe anode of tube 35 in series with a delay circuit 39 whereby 4tube 35energizes relay 3S when the tube becomes conductive. The -delay circuit39 is for the purpose of preventing operation of relay 38 until afterthe pressure in lthe pneumatic system has stabilized, as will be morefully explained.

The contacts 41 of relay 38 lfunction to close a valve operating circuitwhich may be connected to a source of alternating current (not shown)through lines 42 and 43, lines 44 and 45 and a conventional plug 46.ThisV in the tube 17 and manometer 16 to provide an indication ofsystolic pressure. Dump valve 49 operates simultaneously to exhaust airfrom the cuff and the remainder of the pneumatic system shown in FIG.'1. The electric chime 51 sounds simultaneously to provide the personoperating the system with an audible signal indicating that he shouldread the manometer to determine the systolic blood pressure.

lFor providing direct current to the vacuum tube circuit there isprovided a conventional rectifier 53 consisting of a transformer 54connected across the power supply lines 44 and 45. Anode supply voltageis fed to the amplifier stages 32 and 33 through the line 55 while line56 supplies anode voltage to the computer stage 34 as will be describedsubsequently. The he-ater filaments of amplifier stages 32 and 33 andcomputer stage 34 are indicated at 57.

For controlling the operation of the amplifier stages 32 and 33 and thecomputer stage 34 to provide indication of systolic blood pressure thereis provided a control circuit connected across the power supplyconductors 44 and 45 through the conductors 58 and 59. A manuallyoperated emergency switch 60 is connected in series in conductor 44 sothat the entire system may be disabled by deenergizing rectifier 53 andthe circuits connected across conductors 58 and 59. This enables aperson who becomes apprehensive or frightened at any stage of operationof the system to discontinue the operation of the system and freehimself of the cuff 115.

In order to prevent false operation of the system prior to insertion ofa persons hand and arm within the air cuff 15, there is provided a.photoelectric relay circuit 62 having a light source and photoelectriccell connected `across conductors 63. The light source directs a lightbeam across the path which a persons hand and arm must follow when theyare inserted in the cuff whereby the system will not operate until thelight beam is interrupted by the persons hand and arm. The photoelectricrelay circuit l62 controls a normally open relay contact 64 connected inseries with the line 58 through one of the conductors 63 and closeablewith a contact 65 connected through line 66, coin return solenoid 67 toline 59. Thus interruption of the light beam operating the photoelectricrelay circuit 62 closes contacts 64 and 65 energizing the coin returnsolenoid 67. Solenoid 67 functions in a conventional type of coin box topermit the coin to operate a coin operated switch 68 connected in line59. If solenoid 67 is not energized, the coin is automatically returned.

Coin operated switch 68 is closed and held closed for approximatelyfive-tenths of a second by the coin mechanism, thereby to energize amotor control relay 69 connected across the lines 58 and 59.Conventional electrical counter mechanism 70 is connected across relay69 so that it provides a record of each operation of the system. Therelay 69 includes a pair of contacts 72 and 73 connected to lines -58and `59 respectively whereby the compressor motor 74 may be energizedthrough the lines 75 and 76 having contacts closable with contacts 72and 73 respectively. This causes the compressor 10 to operate and buildup the air pressure within the pneumatic system shown in FIG. l.

For maintaining operation of compressor motor 74 and starting theoperation of the amplifier circuit 32, 33, 34, there is provided astarting relay 78 connected across the lines 58 and 59. Relay 78controls normally open switching contacts 79 connected between line 59and line 42 through conductors 80 and 81. Closure of contacts 79connects relays 69 and 78 to conductor 42 through conductors 80 and 81,thereby to hold relays 69 and 78 energized after switch 68 opens. Relay78 also controls normally open contacts 83 connected between line 59 andholding relay 84 which, in turn, is connected to a thermostaticallycontrolled delay switch 85 through line 86. Switch 85 includes aswitching contact 87 connected between line 86 and line 88 which couplesthermostatic delay switch to the power supply line 45 through line 43.

When relay 84 is energized through contacts 83, it closes its normallyopen contacts 90 thereby to establish a self-energizing circuit acrosslines 42 and 43 through conductors 81 and 86, contacts 87 and conductor88. Relay `84 controls tongue 91 normally closed with a contact 92 andoperable by relay 84 to close with contact 93. Relay 84 also controlstongue 94 normally closed with contact `95 and operable by relay 84 toclose with contact 96.

When tongue 91 is closed with contact 92 and tongue 94 is closed withcontact 95, it will be seen that the grounded line 97 is connectedthrough normally closed contacts 98 of relay 78 thereby to ground theanode supply circuit of the thyratron tube 35 through the delay circuit39 and the winding of relay 38. The ground line 97 is also contactedthrough contacts 94, 95 to line 56 and, thus, the anodes of tubes 32 and33 are grounded through line 55, line 56, contacts 94, 95 and line 97.In this manner the amplifier circuit is prevented from operating untilafter maximum pressure is attained in the pneumatic system and highpressure switch 20 has been opened. After the coin is inserted in thecoin mechanism the coin switch 68 closes, energizing relays 78 and 84.Relay 78 opens its contact 98. Meanwhile, relay 84 operates and locks upits own energizing circuit and closes its tongue 91 with contact 93 andits tongue 94 with contact 96. Contact 96 being connected to powersupply 53 through line 100, ground is immediately applied thereto fromline 97. Contact 93 being connected with line 56, closure of tongue 91therewith connects anode voltage to the open contacts 98. Relay 78deenergizes when switch 20 opens, thereby permitting contacts 98 toclose and connect anode supply voltage to the anode of tube 35 throughdelay circuit 319 and relay 38. Simultaneously contact 79 opens,deenergizing relay 69 and opening the circuit of compressor motor 74.

In operation, a person Adesiring to obtain a measurement of his bloodpressure can insert his arm within cuf 15. This action interrupts thelight beam normally actuating the photoelectric relay circuit 62 wherebycontacts 64 and `65 close lto energize coin return solenoid 67. Theperson may then insert a coin return solenoid 67. switch 68. Theemergency switch 60 being normally closed, closure of switch 68energizes the motor control relay 69 closing its contacts to start thecompressor motor 74. Simultaneously, the counter 70 is energized torecord a cycle of operation of the system.

Then the compressor 10 is started .by motor 74, air pressure 'builds upin the pneumatic system to a maximum of approximately 220 millimeters ofmercury, at which time the high pressure limit switch 20 opens to stopcompressor motor 74. In this manner the cuff 15 is inflated to a degreesucient to stop circulation of blood in the veins and arteries of thepersons arm. Also, the transducer 30 is engaged with the persons arm infirm contact therewith. The cuff may be a generally cylindrical deviceformed of rubber and designed in such a manner as to contract internallyunder air pressure and collapse the blood Vessels of the persons arm toan extent that flow of blood is substantially stopped.

Meanwhile, closure of the coin switch 68 energizes the starting relay 78which operates its contacts 79 and 83 to energize and lock up theswitching relay 84. Contact 98 of relay 78 is opened thereby to preventapplication of anode potential to the anode of thyratron 35. Withoutsuch anode potential, the thyratron cannot respond to electrical Wavesgenerated by the transducer in response to pulsations of air within thepneumatic system while it is being inflated by the compressor.

When limit switch 20 opens in response to maximum pressure, relay 78 isdeenergized, thereby permitting all of its contacts to assume theiroriginal positions, contact 98 closing to complete the anode potentialcircuit to thyratron 35. Meanwhile, relay 84 operated its tongues 91 and94 to connect anode potential from rectifier 53 to contact 98.

The delay circuit `39 provides a slight delay in application of anodepotential to thyratron 35, permitting transient pulsations within thepneumatic system to decay so that when thyratron 35 is finally energizedno false operation is possible.

As the previously described functions occur, the bleed rate controlvalve 24 exhausts air from the pneumatic system, lowering the pressuretherein at a rate of approximately millimeters of mercury per second.The pressure in the pneumatic system continues to decrease until thesystole ocurs, or if the person is incapable of producing a systolicpulse within normal pr-essure range, the normally open low pressureswitch 22 operates at a pressure of 105 millimeters of mercury andcloses to connect the cathode of tube 35 to ground, thereby to preventactuation thereof. When a systole occurs within the normal pressurerange, there is a throbbing motion of the blood passing through all ofthe vessels in the persons extremity within the cuff and under thetransducer and the transducer 30 4generates a low motional voltage wave,corresponding to this throbbing or pulsating action, which is impressedon the grid of amplifier 32. The signal wave is amplified in amplifierstages 32 and 33 and applied to the control grid of thyratron 35. Theamplified wave changes the potential on the grid to a degree suicient toiire thyratron 35 whereby the tube conducts, causing Ianode current toiiow through relay 38.

At this point sufficient current liows through relay 38 to cause contact41 to close, applying voltage from lines 42 and 43 to the systolic valvecontrol winding 47 and the dump valve control winding 48, The systolicvalve 18 is closed isolating the manometer 16. As the pressure decreasedin the pneumatic system, the reading on the manometer also decreased sothat closure of valve 18 stops the needle of the manometer at the pointindicating the systolic pressure of the person. At the time that thesystolic valve is closed, transformer 50 is energized to actuate theelectrical chime 51 which serves to notify the person that he shouldread the systolic pressure indicated by the manometer.

The manometer reading is maintained for approximately 20 seconds atwhich time the thermal delay relay 85 will have opened its contacts 87deenergizing relay 84 and restoring the entire system to its idlecondition.

From the foregoing description it will be readily apparent that thisinvention provides a coin operated means of indicating blood pressurewherein completely adequate safeguards are provided for preventing falseindications of blood pressure and any discomfort to the person operatingthe device. The photoelectric detection device 62 prevents operation ofthe indicating system until the persons arm is in proper position withinthe cuff. The system includes means 60 for allowing the person torelease himself at any time should he become uncomfortable or fearful.Also false indications of blood pressure are prevented by delay circuit39 prior to stabilization of the pneumatic system. In addition, maximumand minimum pressures are established within the pneumatic system byhigh pressure limit switch 20 and low pressure switch 22, respectivelyso that there can be no excessive yand uncomfortable pressure on thepersons arm and so that excessively low pressures will not create falseindications.

The invention claimed is:

1. A systolic pressure measuring system comprising in combination apneumatic system for providing an indication of a persons systolicpressure and a coin operated electrical control system for initiatingoperation of said pneumatic system and terminating a cycle o-f operationof said pneumatic system when systolic pressure has been indicated, saidpneumatic system comprising an inliatable `cuii for receiving a personsarm and .applying pressure thereto for stopping circulation of bloodtherein, a transducer associated with said cuff for pressure contactwith lthe persons arm, an air compressor, a manometer, an electricallyoperable valve between said compressor and said manometer operable toisolate said manometer from said compressor, and a bleeder valve adaptedto reduce pressure in said pneumatic system lat a controlled rate, saidcoin operated control system comprising an amplifier coupled to saidtransducer for producing an electrical wave as a function of the personssystolic Iblood pressure, switch means coupled to said amplifier andsaid valve and responsive to said wave for operating said valve toisola-te said manometer when pressure equal to the persons systolicpressure occurs, coin loperated switch means in said control system 'forinitiating operation of said pneumatic system and switch means coupledto said pneumatic system and said amplifier and responsive to apredetermined pressure in said pneumatic system for initiating operationof said amplifier.

2. The systolic pressure measuring system of claim 1 in which saidcontrol system includes means coupled Ito said ampliier for delayingoperation of said wave producing means until pressure has beenstabilized in said pneumatic system.

3. The systolic pressure measuring system of claim l in which saidcontrol system includes relay switching means coupled to said ampliiierfor deenergizing said wave producing means while said pressure applyingmeans is initially operating and thereafter energizing said waveproducing means.

4. The systolic pressure measuring system of claim 1 in which saidcontrol system includes switch means for maintaining operation of saidpressure indicating means for a predetermined period of time andthereafter terminating operation of said pressure indicating means andrestoring said control system and said pneumatic system to idlecondition.

5. The systolic pressure measuring system of claim 1 in which saidcontrol system includes photoelectric means adjacent said cuff fordetecting the presence of the persons arm, in said pressure applyingmeans and conditioning said coin operated switch means for actuation bya com.

6. The systolic pressure measuring system -of claim l in which saidpneumatic system includes la high pressure limit switch operable a-t apredetermined maximum pressure within said pneumatic system, and saidcontrol system includes means responsive Ito said high pressure limitswitch for terminating iniiation of said pneumatic system when saidmaximum pressure is attained, and means coupled to said ampliiier fornormally deenergizing said wave producing means and operable by saidhigh pressures limit switch for energizing said wave producing meansafter said maximum pressure is attained in said pneumatic system.

References Cited in the iile of this patent UNITED STATES PATENTS1,946,985 Parker et al. Feb. 13, 1934 2,826,191 Burns Mar. 11, 19582,865,365 Newland et al Dec. 23, 1958

1. A SYSTOLIC PRESSURE MEASURING SYSTEM COMPRISING IN COMBINATION APNEUMATIC SYSTEM FOR PROVIDING AN INDICATION OF A PERSON''S SYSTOLICPRESSURE AND A COIN OPERATED ELECTRICAL CONTROL SYSTEM FOR INITIATINGOPERATION OF SAID PNEUMATIC SYSTEM AND TERMINATING A CYCLE OF OPERATIONOF SAID PNEUMATIC SYSTEM WHEN SYSTOLIC PRESSURE HAS BEEN INDICATED, SAIDPNEUMATIC SYSTEM COMPRISING AN INFLATABLE CUFF FOR RECEIVING A PERSON''SARM AND APPLYING PRESSURE THERETO FOR STOPPING CIRCULATION OF BLOODTHEREIN, A TRANSDUCER ASSOCIATED WITH SAID CUFF FOR PRESSURE CONTACTWITH THE PERSON''S ARM, AN AIR COMPRESSOR, A MANOMETER, AN ELECTRICALLYOPERABLE VALVE BETWEEN SAID COMPRESSOR AND SAID MANOMETER OPERABLE TOISOLATE SAID MANOMETER FROM SAID COMPRESSOR, AND A BLEEDER VALVE ADAPTEDTO REDUCE PRESSURE IN SAID PNEUMATIC SYSTEM AT A CONTROLLED RATE, SAIDCOIN OPERATED CONTROL SYSTEM COMPRISING AN AMPLIFIER COUPLED TO SAIDTRANSDUCER FOR PRODUCING AN ELECTRICAL WAVE AS A FUNCTION OF THEPERSON''S SYSTOLIC BLOOD PRESSURE, SWITCH MEANS COUPLED TO SAIDAMPLIFIER AND SAID VALVE AND RESPONSIVE TO SAID WAVE FOR OPERATING SAIDVALVE TO ISOLATE SAID MANOMETER WHEN PRESSURE EQUAL TO THE PERSON''SSYSTOLIC PRESSURE OCCURS, COIN OPERATED SWITCH MEANS IN SAID CONTROLSYSTEM FOR INITIATING OPERATION OF SAID PNEUMATIC SYSTEM AND SWITCHMEANS COUPLED TO SAID PNEUMATIC SYSTEM AND SAID AMPLIFIER AND RESPONSIVETO A PREDETERMINED PRESSURE IN SAID PNEUMATIC SYSTEM FOR INITIATINGOPERATION OF SAID AMPLIFIER.